Greenish-yellow dye.



TM "ED STATES PATENT OFFICE.

PAUL VOLKMANN, 0F ELBERFELD, GERMANY, ASSIGNOR TO FARBENFABRIKEN VORM. FRIEDR. BAYER & 00., OF ELBEREELD, GERMANY, A CORPORATION OF GERMANY.

: GREENISH-YELLOW DYE.

No Drawing.

of a new yellow azo dye by condensing 2 molecules of phenyl-hydrazin-orth0-sulfonic acid with dioxytartaric acid.

The dye has in a free state most probably the formula:

C6H,.SO,H

I? GO o--- H-N=N-C8H,.SO,H

OOH

It is characterized by its good fastuess to light and its valuable greenish-yellow shade.

To illustrate my rocess, I can proceed as follows, the parts eing by weight :150.6 parts of phenylhydrazin-ortho-sulfonic acid are stirred up with 1,000 parts of water and G0 parts of sulfuric acid (60 136.). To this mixture 106 parts of the sodium saltvof dioxy-tartaric' acid are added. The mixture is stirred for 1 hour and is then boiled for 2 Specification of Letters Patent. Application filed December 18, 1909. Serial No. 533,876.

wool bright greenish yellow level shades,

Patented Sept. 6, 1910.

hours. The .dye is salted out, filtered 0H, mixed with sodium carbonate to make the neutral sodium salt and dried. shapeof its sodium salt a yellow powder soluble in concentrated sulfuric acid with a yellow color. Upon. reduction with staunous chlorid and hydrochloric acid the dye is decomposed, auilin-ortho-sulfonic acid and 1-ortho-sulfopheuyl-3-carboxy-4-a1uino- 5-pyrazolone are obtained. It produces 011 fast to light.

I claim:

The herein described new coloring matter obtainable from phenylhydraziu-orthosulfonic acid and dioxytartaric acid, which is in dry state in the shape of its sodium salt a yellow powder soluble in concentrated sult'uric acid with a yellow color; yielding upon reduction with stannous chlorid and hydrochloric acid anilin-ortho-sulfonio acid and 1-ortho-sulfophenyl-3-carboXy 4-a1nino o-pyrazoloueg and dyeing wool bright greenish yellow described.

In testimony whereof I have hereunto set any hand in the presence of two subscribing witnesses.

. PAUL VOLKMANN. Witnesses:

. O'r'io Kiimo,

CHAS. J. WRIGHT.

shades, substantially as 35 It IS in the v 

